The present invention relates to an improved oxygen absorber for absorbing oxygen primarily in ambient temperature dry environments and which will also function satisfactorily in in both low temperature environments and in moist environments.
By way of background, particulate iron is known as an oxygen absorber because it readily combines with oxygen. In the past, various types of particulate iron have been used, including hydrogen reduced iron, electrolytically reduced iron, atomized iron, and milled pulverized iron. However, the hydrogen reduced iron, the atomized iron and the milled pulverized iron absorb oxygen relatively slowly. The electrolytically reduced iron absorbs oxygen faster, but at lower temperatures at which foods are normally refrigerated it absorbs oxygen at a slower rate than desired to remove the oxygen before the initial stages of food spoilage commence. Furthermore, in dry environments it is necessary to supply moisture for producing an electrolytic action which is necessary for activating the oxygen-absorbing action of the iron. However, silica gel which has been used in the past for adsorbing moisture from a moist environment cannot be used for a plurality of reasons. The first reason is that if it contains sufficient moisture to supply such moisture, it is not flowable and thus cannot be used efficiently in a manufacturing process. The second reason is that if it contains a lesser amount of moisture so that it remains flowable, it will not give this moisture up for combining with a salt to produce an electrolyte, and further, in a dry environment it will not have a source of moisture from which it can adsorb the necessary moisture for activating oxygen absorption. Furthermore, the envelopes of certain prior oxygen-absorbing packets were deficient for use in dry environments in that they permitted moisture to escape from a moisture-containing oxygen-absorbing composition which diminished the moisture available for producing the required electrolytic action.